1. Field of the Invention
The present invention relates to industrial vehicles, such as lift industrial vehicles; and more particularly to a system for sensing performance characteristics of an industrial vehicle and using those characteristics to manage the operation of the vehicle.
2. Description of the Related Art
Industrial vehicles of various types, including material handling vehicles, are used to move items inside a factory, a warehouse, a freight transfer station, a store, or other type of facility. Traditionally these industrial vehicles were controlled by an on-board human operator. In order to effectively and efficiently operate a warehouse, for example, it is important to ensure that the equipment and operators are as productive as possible. For a warehouse to compete on the global level, continually improving productivity of industrial vehicle use is vital to reducing costs. To meet these goals, warehouse management systems are frequently employed to control inventory, ensure proper maintenance of equipment, and to monitor operator and equipment efficiency. In these warehouse management systems, a centralized computer system monitors inventory flow, use of the industrial vehicle, vehicle maintenance status, and operator performance.
To provide these functions, data was gathered from each industrial vehicle. In order to gather the data, sensors on the industrial vehicle fed data to a dedicated onboard computer. The data was stored in that computer and occasionally transferred from storage to an central computer system at the facility in which the industrial vehicle operated. The central computer system analyzed the data from all the vehicles at the facility to determine the performance of each vehicle and of the different operators. The data analysis also indicated when maintenance and repair of a vehicle was required,
Industrial vehicles have gotten more sophisticated and a new category of autonomous guided vehicles has evolved. An autonomous guided vehicle (AGV) is a form of mobile robot that transports goods and materials from one place to another in a constrained environment, such as a factory or a warehouse. Some AGV's followed a wire buried in the floor and thus were limited to traveling along a fixed path defined by that wire. Guidance technology developed further so that the vehicle was not confined to a fixed path. Here reference markers, referred to as fiducials, were placed periodically along various paths that could be traveled by the AGV. In one implementation, each fiducial had unique appearance or optically readable code, e.g. a unique barcode. An AGV was assigned a path defined by a sequence of the fiducials along that path. An optical sensor on the AGV sensed adjacent fiducials as the vehicle travelled and the unique appearance or code of each fiducial enabled the vehicle to determine its present location in the facility and the travel direction along the assigned path.